sector

American  

[sek-ter] / ˈsɛk tər /

noun

• sectors
  plural

1. Geometry. a plane figure bounded by two radii and the included arc of a circle.

2. a distinct part, especially of society or of a nation's economy.

   the housing sector; the educational sector.

3. a section or zone, as of a city.

4. Military. a designated defense area, usually in a combat zone, within which a particular military unit operates and for which it is responsible.

5. a mathematical instrument consisting of two flat rulers hinged together at one end and bearing various scales.

6. Machinery. a device used in connection with an index plate, consisting of two arms rotating about the center of the plate and set to indicate the angle through which the work is indexed.

7. Astronomy. an instrument shaped like a sector of a circle, having a variable central angle and sights along the two straight sides, for measuring the angular distance between two celestial bodies.

8. Computers. a portion of a larger block of storage, as 1/128 of a track or disk.

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verb (used with object)

1. to divide into sectors.

sector British  

/ ˈsɛktə /

noun

1. a part or subdivision, esp of a society or an economy

   the private sector

2. geometry either portion of a circle included between two radii and an arc. Area: 1/ 2 r ²θ, where r is the radius and θ is the central angle subtended by the arc (in radians)

3. a measuring instrument consisting of two graduated arms hinged at one end

4. a part or subdivision of an area of military operations

5. computing the smallest addressable portion of the track on a magnetic tape, disk, or drum store

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sector Scientific  

/ sĕk′tər /

1. The part of a circle bounded by two radii and the arc between them.

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Other Word Forms

Derived Forms

• subsector
  noun
• sectoral
  adjective

Inflected Forms

Nouns

• sectors
  plural

Etymology

Origin of sector

First recorded in 1560–70; from Late Latin, from Latin: “cutter,” from sec(āre) “to cut, divide” + -tor -tor

Explanation

Sector sounds like section, doesn't it? That's a good way to remember that a sector is a specific part of society or the economy, made up of similar elements — like the health care sector or the education sector. Our most common use of the word sector refers to a society’s divisions. For example, our economy is divided into the private sector (privately-owned interests) and the public sector (government). Other than that, the word also has many technical applications in math and science. From the Latin verb secare, "to cut," sector was applied long ago to math as a section of a circle, which carried through to military language as "a circle around a headquarters."

Example Sentences

See Examples For:

sector sectors

Did they rise so much because the economy is strong, jobs are plentiful and money is pouring into the artificial-intelligence sector?

From The Wall Street Journal ● Sep. 20, 2026

“We remain overweight the group and believe investors should consider adding positions even with $100-a-barrel oil prices,” William Blair energy sector analyst Neal Dingmann wrote in recent research note, citing the same double-digit free-cash-flow yields.

From MarketWatch ● Sep. 19, 2026

She wants to encourage more women to aim for senior leadership roles in manufacturing and engineering sector.

From BBC ● Sep. 18, 2026

TA Securities maintains a neutral rating on Malaysia’s semiconductor sector, pegging Dagang NeXchange as its top pick.

From The Wall Street Journal ● Sep. 18, 2026

Technical academies are well represented, most of them from the for-profit sector that has been under scrutiny in recent years because students too often emerge with tens of thousands of dollars of debt—but not jobs.

From "Drama High" by Michael Sokolove

Roberts argued there was a "very big opportunity" for manufacturers to redirect skills, factories and investment into the UK's expanding aerospace and defence sectors.

From BBC ● Sep. 20, 2026

It also aims to help build a broader bioengineered, silicon-based materials ecosystem by connecting researchers, industry partners, policymakers, educators, and future innovators across multiple disciplines and sectors.

From Science Daily ● Sep. 19, 2026

European stock indexes largely opened lower, though AI-related shares gained, as momentum in defensive sectors stalled after strong gains in the last session.

From The Wall Street Journal ● Sep. 18, 2026

Gibbons said the information technology and energy sectors have proved to be the best performing on average one year after a rate rise.

From MarketWatch ● Sep. 17, 2026

Someone living in Blueridge or Lake or Winter or Alta, sectors all recently affected by the plague.

From "Legend" by Marie Lu

Related Words

• district
• part
• region
• zone